Process of decolorizing tannin extracts.



UNI ED STATES PATENT onion.

ADOLF HUGENDUBEL, OF STUTTGART-FEUERBAOH, GERMANY, ASSIGNOR TO THE FIRM OF CARL FEUERLEIN, OF STUTTGART-FEUERBAOH, GERMANY PROCESS OF DECOLORIZING TANNIN EXTRAC TS,

Specification of Letters Patent.

Patented Nov. 17, 1908.

Application filed December 17, 1907. Serial No. 496,399.

T all whom it may concern:

Be it known that I, ADOLF HUGENDUBEL,

a citizen of the German Empire, residing at Stuttgart-Feuerbach, in the Kingdom of \Viirtemberg, Empire of Germany, have mvented certain new and useful Improvements in Processes of Decolorizing Tannin Extracts; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use 'the same.

A hitherto generally employed process of decolorizing tannin extract consists in add ing sodium sulfite (M 80 and sodium bin sulfite (NaHSO to the tannin extract, In spite, however, of the adding of large quantities or sulfite the decolorizing effect is only I 3,- pages 526, 536, 546 and 567) are derived from chromous protoxid (C1'()) and are characterized by a strong reducing power, so that even a very small addition of this substance to tannin extract, for instance, mangrove extract, sufiices for obtaining a complete and permanent decolorization. For the attainment of the object in hand, the chromous salts of the' weakacids, such as chromous acetate (Cr(CH CO or chromous sulfite (CrSO,),fi are the most suitable, but chromous chlorid j(OrCl,) and chromous sulfate (C1SO may also be employed. The process also has the greatadvantage. that no loss of tannin takes place, as numerous analyses have shown.

Emamplcs.

[. Decolom'eiing of mangrove ezctmct.To

1000 kilograms of mangrove extract of 25 Baum, 5 7.5' kilograms of chromous acetate are added, under agitation, in the form of a paste. The decolorizing takes place even when cold, but is referably assistedby heating to about 70 H. Decolom'zz'n of quebracho extract.- 1000 kilograms o quebracho extract of 25 Baum are, as in Example I, treated with 1-2 kilograms of chromous acetate, or the thin chromous acetate paste is introduced. into the vacuum evaporator.

Having thus fully described my invention,

what I claim is:

The process of decolorizmg tannin extracts which consists in treatlng the same with chromous compounds derived from chromous protoxid (CrO).

- ln testimony whereof I afiix my signature,

in presence of two witnesses.

ADQLF HUGENDHBEL.

Witnesses i Y JEAN GULDEN, HnRM. Horrn. 

